Messages in this thread | | | Date | Fri, 17 Dec 2010 18:51:28 -0500 | From | Vivek Goyal <> | Subject | Re: kdump broken on 2.6.37-rc4 |
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On Fri, Dec 17, 2010 at 03:34:05PM -0500, Vivek Goyal wrote: > On Fri, Dec 17, 2010 at 12:06:23PM -0800, Yinghai Lu wrote: > > On 12/17/2010 12:01 PM, Vivek Goyal wrote: > > > On Fri, Dec 17, 2010 at 11:52:11AM -0800, Yinghai Lu wrote: > > >> On 12/17/2010 11:50 AM, Vivek Goyal wrote: > > >>> On Fri, Dec 17, 2010 at 11:46:08AM -0800, Yinghai Lu wrote: > > >>>> On 12/17/2010 11:39 AM, H. Peter Anvin wrote: > > >>>>> On 12/17/2010 10:21 AM, Yinghai Lu wrote: > > >>>>>>>> > > >>>>>>>> Do we have actual testing for how high the 64-bit kernel will load? > > >>>>>>> > > >>>>>>> I will do some experiments on my box today and let you know. > > >>>>>> > > >>>>>> if bzImage is used, it is 896M. > > >>>>>> > > >>>>> > > >>>>> Why? 896 MiB is a 32-bit kernel limitation which doesn't have anything > > >>>>> to do with the bzImage format. > > >>>>> > > >>>>> So unless there is something going on here, I suspect you're just plain > > >>>>> flat wrong. > > >>>> > > >>>> kexec-tools have some checking when it loads bzImage. > > >>>> > > >>> > > >>> Yinghai, > > >>> > > >>> I think x86_64 might have just inherited the settings of 32bit without > > >>> giving it too much of thought. At that point of time nobody bothered > > >>> to load the kernel from high addresses. So these might be artificial > > >>> limits. > > >> > > >> good point. will check that. > > > > > > Yinghai, > > > > > > On x86_64, I am not seeing "Crash kernel" entry in /proc/iomem. > > > > > > I see following in dmesg. > > > > > > "[ 0.000000] Reserving 128MB of memory at 64MB for crashkernel (System > > > RAM: 5120MB)" > > > > > > Following is my /proc/iomem. > > > > > > # cat /proc/iomem > > > 00000100-0000ffff : reserved > > > 00010000-00096fff : System RAM > > > 00097000-0009ffff : reserved > > > 000c0000-000e7fff : pnp 00:0f > > > 000e8000-000fffff : reserved > > > 00100000-bffc283f : System RAM > > > 01000000-015d1378 : Kernel code > > > 015d1379-01aee00f : Kernel data > > > 01bc8000-024b4c4f : Kernel bss > > > bffc2840-bfffffff : reserved > > > > > > So there is RAM available at the requested address still no entry for > > > "Crash Kernel". This is both with 2.6.36 as well as 37-rc6 kernel. I am > > > wondering if insert_resource() is failing here? > > > > > > > also could be memblock_x86_reserve() fail ... > > > > Please check attached debug patch... > > > > looks like memblock_x86_reserve() is fine. Following is dmesg output with > your debug patches applied.
Hi Yinghai,
Please ignore this. The problem was with my setup with some user space script setting kexec_crash_size = 0 hence freeing up the memory. I think it is time to put a kernel message when memory is freed/shrinked. I wasted a lot of time debugging it.
Sorry for the noise here.
thanks Vivek
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